A piezoelectric energy harvester in a novel wristwatch-like device. Credit: Penn State
Aug. 31, 2018 (Phys.org) -- A wearable energy-harvesting device could generate energy from the swing of an arm while walking or jogging, according to a team of researchers from Penn State's Materials Research Institute and the University of Utah. The device, about the size of a wristwatch, produces enough power to run a personal health monitoring system.
"The devices we make using our optimized materials run somewhere between five and 50 times better than anything else that's been reported," said Susan Trolier-McKinstry, the Steward S. Flaschen Professor of Materials Science and Engineering and Electrical Engineering, Penn State.
Energy-harvesting devices are in high demand to power the millions of devices that make up the internet of things. By providing continuous power to a rechargeable battery or supercapacitor, energy harvesters can reduce the labor cost of changing out batteries when they fail and keep dead batteries out of landfills.
Certain crystals can produce an electric current when compressed or they can change shape when an electric charge is applied. This piezoelectric effect is used in ultrasound and sonar devices, as well as energy harvesting.